Magazine Archive

Home -> Magazines -> Issues -> Articles in this issue -> View

Article Group:
Recording World

Lexicon PCM 70 Digital Effects Processor

Studio Test

A bargain? From Lexicon? Curtis Schwartz thinks so

Imagine having six digital delay lines, six chorus units, digital plate, room and chamber reverberation programs, MIDI interface, more than 70 different parameters to control over 40 preset digital effects, 50 user programmable memories and all in a single 1u 19" rackmounting unit...

This is a brief outline of Lexicon's latest piece of outboard equipment, the PCM 70, which is now available at a price which recording studios and musicians alike will find very attractive.

The PCM 70, rather than being a straightforward device along the lines of Lexicon's PCM 60 (an excellent preset digital reverberation device) has much more in common with Lexicon's flagship digital reverb/effects device, the 224XL.

The 224XL digital reverb/effects processor is widely regarded as providing the ultimate in digital reverb as well as a multitude of special effects. At a little under £11,000 though, it is not cheap. It has earned respect throughout the industry not only because of the superb range of digital reverberation it can produce, but also because of its other capabilities as a very versatile effects processor able to produce a wide range of sounds which, until the advent of the PCM 70, were unique.

The 224XL's multi-chorus programs have a quality which no other signal processor yet can touch, as well as multi-delay programs from which come their famous Resonant Chord programs.

Unfortunately, in order to be able to use the full power of the 224XL's chorus or multi-delay programs in a mix meant that you had to more or less forego its primary function as a very powerful digital reverb. This accounts for why many people hire in several 224XLs at one time (Paul McCartney has been known to hire in six or more for a single mix).

Enter Lexicon's PCM 70, designed to provide all the 224XL's effects processing features in addition to providing a selection of plate, room and chamber reverb programs (and many of their permutations) in its own right.

The PCM 70's front panel is deceptively simple, consisting of only the input level/meter on the left, a green display, a Soft Knob, up/down switches, 10 numbered switches and four mode switches.

The programs are configured into six sets of programs, called Rows, each with their own specialised set of parameters. Each of these Rows are accessed by the up/down switches to the right of the Soft Knob, and are divided into a maximum of 10 columns (selected by the 10 numbered buttons). In each of the columns are a variation of the Row's main program, which might have further variations of parameter control, such as the Infinite Reverb columns found amongst the Rich Chamber Reverb row of programs.

In the first Row of programs are the Chorus and Echo programs. These consist of two 432 millisecond delay lines with six taps (essentially working as six independent delay lines with independent delay times, etc).

Each of these six delay taps can provide chorusing effects, whilst also being individually pannable over the PCM 70's stereo outputs. Each delay has its own parameters for level, feedback, chorus, pan, and delay time. In addition to this, Row One also provides master control over the delays' diffusion (a sort of 'smearing' effect), high frequency cut-off, chorusing depth and chorusing modes (a single parameter which, via the Soft Knob, can control how many delays are chorused as well as the chorus' waveshapes).

The parameters themselves are accessed by pressing either the Program or Register button (depending on which bank of memories you are in at the time). The up/down and numbered switches can then access the parameters in the same way as they select programs. Once you have the parameter you wish to edit displayed on the screen, the Soft knob is then used to increase/decrease its current setting.

This degree of control over multi-effects is capable of producing some great effects for vocals, whilst also being able to bring to life the dullest guitar or the thinnest sounding synths. I found the multi-chorus effect to be ideally suited as a subtle effect which you only really notice when you switch it off – the kind of effect that I found myself using all the time on the DX7.

In the second Row are variations of Row One's Chorus and Echo programs, called the Multiband Delay programs. These have almost the same parameters as are found in Row One, except that the six delays can go up to 936ms rather than 432ms. Also, each delay has its own set of Lo Cut and Hi Cut filters and only two of the delays can be fed back. The longer delay time of Row Two makes these programs more suited to more obvious repeat delay effects, and this is taken one stage further by the last two columns which are called Shuffle BPM and Bouncing BPM. The 'BPM' stands for Beats Per Minute and it is in beats per minute that these patches' delay times are set, rather than in milliseconds. When the master BPM is set, each of the six delay lines can be set at its own fraction of the master BPM, ie delay one could be set at 8/24, delay two at 12/24, delay three at 2/24, etc. I found this to be an excellent facility for those of us working with drum machines or sequencers, whilst also being an extremely useful effect to use during a mix when it's fairly typical to use one or two DDLs to set up echoes in time with the track – the PCM 70 does it all for you.

In the third Row are the Resonant Chord programs and these produce an effect which was hitherto only available on the big 224XL. What they do is to produce a kind of resonance on each delay which can be set to play a specific note. This can therefore be set to produce chords, arpeggios or just 'funny sounds' when stimulated by a signal at the input stage.

This can be quite a whacky effect to use on guitar or keyboards, but I found it tended to work best on transient program material such as drums where it can really go OTT. By the way, this was the effect on Laurie Andersen's voice on Oh Superman.

The next three Rows of programs are the digital reverbs – all mono in/stereo out with much greater parameter control than any other digital reverbs under twice the PCM 70's price.

Row four has the first reverb program – Concert Halls. These are programs which give a strong sensation of space – and are most suited for giving sounds their own dimension in a mix. There is control over pre-delay time, diffusion, room size, attack, definition, chorusing and hi cut. The reverb itself is divided between mid and low reverb, each with their own time controls, stop times (I'll explain that in a moment) and programmable cross-over point. If that isn't enough, you can also have two early reflection delay lines with their own delay time, level control, and each one is assigned to one of the PCM 70's outputs. And there's more...

Another control parameter is Decay Optimisation – a clever facility available to all the reverb programs and this alters the program characteristics in response to changes in input level. This simply has the effect of 'tidying up' reverb according to the type of signals it is reverberating.

The final control parameter is the Gate. This is much more than simply a programmable gate as it works in conjunction with the settings of the low and mid reverb stop times. This, in effect, means that you can have individual gating on the low and/or high reverberation, which is a very versatile facility – superb for just about any kind of gated reverb effects you can imagine, in addition to giving added control over more 'normal' (whatever that is) reverberation.

The fifth Row is for the Rich Chamber reverberation programs. Whilst these programs differ to the Concert Hall programs in having three rather than two early reflections as well as no chorusing facility, the main difference is in the 'character' of the reverberation itself. The Rich Chamber programs are relatively dimensionless and their decay characteristics are quite smooth in comparison to the Concert Halls.

Infinite Reverb is a patch that can hold reverberation indefinitely – hit a single note on your guitar, reverberate it, and then hold the reverb. The reverb will sustain until switched off. Then do the same with a second note, and thereby build up a chord of pure reverb. A delicious effect...

The last of the reverb programs are the Rich Plates. These are unlike the others in that their sound quality is rather bright with a high initial diffusion and a fair bit of coloration – pretty much what you get from real echo plates. The parameters available are the same as those on the Rich Chambers. Of the three reverb programs, this is probably the setting most ideally suited to percussion.

The sixth row is dedicated to MIDI effects, which is another area in which the PCM 70 really scores. Via the MIDI Row's controls you can not only switch between any of the programs either among the Presets bank or from the 50 user registers, but the PCM 70 also makes it possible for you to assign up to 10 of its parameters to either individual or common data entry controls on your MIDI device. This could be a DX7's pitch wheel, modulation pedal, data entry slider, as easily as it could be the Roland Guitar Synth's data entry control. I suppose it isn't too hard to begin to imagine the possibilities that this kind of control could offer – assign feedback amount to aftertouch, assign chorus intensity to the swell pedal, control infinite reverb on/off to a breath controller, etc...

There really isn't enough space here for me to go into as much detail as either I'd like or that the Lexicon PCM 70 deserves. Even over the two weeks in which I have been lent the unit I have not yet exhausted the PCM 70's potential.

The reverb's bandwidth extends up to 15kHz which I found to be satisfactory for all but the most outrageous reverb settings, and the amount of parameter control over all the different programs was superb.

FOR: Sounds; versatility; size; relative ease of use


The PCM 70 should be thought of, however, primarily as an effects device, as it is in its element when acting as six chorus units, or providing multi-delays darting across the stereo spectrum. Even the reverb programs seem to be best suited for gated effects or infinite reverb.

All in all, never have so many effects been offered in one unit for so low a price, and this really must be the next best thing to having Lexicon's £11,000 224XL. Think of it that way and £2,176 sounds like a real bargain. Doesn't it?

RRP: £2,176

Also featuring gear in this article

Previous Article in this issue

Home Taping

Next article in this issue

Track Record: Queen

International Musician & Recording World - Copyright: Cover Publications Ltd, Northern & Shell Ltd.


International Musician - Feb 1986

Recording World

Gear in this article:

Studio FX > Lexicon > PCM70

Gear Tags:

Digital FX

Feature by Curtis Schwartz

Previous article in this issue:

> Home Taping

Next article in this issue:

> Track Record: Queen

Help Support The Things You Love

mu:zines is the result of thousands of hours of effort, and will require many thousands more going forward to reach our goals of getting all this content online.

If you value this resource, you can support this project - it really helps!

Donations for November 2021
Issues donated this month: 0

New issues that have been donated or scanned for us this month.

Funds donated this month: £46.00

All donations and support are gratefully appreciated - thank you.

If you're enjoying the site, please consider supporting me to help build this archive...

...with a one time Donation, or a recurring Donation of just £2 a month. It really helps - thank you!

Small Print

Terms of usePrivacy